Ensure to review the job posting before the interview to know whether a master's degree is a requirement at present, whether having a master's degree would be an asset, or whether it will be required in the future.
If it is a requirement, you should know a master's degree will eventually be required, even if you applied for the position with only a bachelor's degree. In this case, you should expect your employer to prefer a candidate who will be pursuing a master's degree at some point in time.
If you already know a master's degree is a requirement but you are fortunate enough to be interviewed despite only having a bachelor's degree, and you indeed wish to eventually study for a master's degree, prepare an answer beforehand. Add that the pursuit of this master's degree will not interfere with your work and that you are serious about your application. Employers are looking for commitment.